"The Blessed Lord said: I instructed this imperishable science of yoga to the sun god, Vivasvan, and Vivasvan instructed it to Manu, the father of mankind, and Manu in turn instructed it to Iksvaku." [Bhagavad-gita, 4:1]
The process of linking onself with the supreme is called yoga, and has been practiced since time immemorial, handed down via the chain of disciplic succession, as described in the above verse from the Bhagavad-gita. The attainment of perfection in yoga may be compared to a ladder which helps one rise to the topmost rung of spiritual realization. The ladder begins from the lowest material condition of the living entity and elevates one to perfect realization in pure spiritual life. According to various attainments, different parts of the ladder are known by different names. But all in all, the complete ladder is called yoga and may be divided into three parts, namely jnana-yoga, dhyana-yoga, and bhakti-yoga.
In the beginning, attempts to enter into meditation through regulated behavior and practice of sitting postures, are considered fruitive material activities. All such activities are directed toward achieving perfect mental equalibrium, and control of the senses. When one is accomplished in the practice of meditation, he ceases all disturbing mental activities.
"A person is said to have attained yoga when, having renounced all material desires, he neither acts for sense gratification nor engages in fruitive activities." [Bhagavad-gita, 6:4]
The purpose of practicing yoga is to control the mind in order to make it a friend in discharging the human mission. Unless the mind is controlled, the practice of yoga (for show) is simply a waste of time. Physical health and psychological improvement are by-products of yoga practice, but not the goal. As long as ones mind remains an unconquered enemy, one has to serve the dictations of lust, anger, avarice, illusion, etc.
"For one who has conquered the mind, the mind is the best of friends, but for one who has failed to do so, his very mind will be the greatest enemy." [Bhagavad-gita, 6:6]
Yoga practice entails meeting the Paramatma within the heart and then following His dictation. Therefore, the Lord gives instruction to Arjuna as to how one can come to that position by the practice of mysticism or yoga, known as astanga-yoga. This yoga practice is divisible into an eightfold procedure called yama, niyama, asana, pranayama, pratyahara, dharana, dhyana, and samadhi. In astanga-yoga, one has to drive out the allurements of the senses, such as sound, taste, form, touch, and smell, by the pratyahara (breathing) process. The movement of breath is restrained by neutralizing the movement of air within the body. By practicing asana (sitting postures), the yogi attains a meditative trance, fixing the mind with single-pointed focus. A genuine practitioner of astanga-yoga will live in a secluded place, completely free from sensual distraction, and stringently curbing the bodily cravings for excessive eating, sleeping, or sex indulgence. Devoid of all material desires born of false ego, the progressive yogi will control the senses on all sides, by the power of his mind.
By practice of yoga one becomes gradually detached from material concepts. This is the primary characteristic of the yoga principle. And after this, one becomes situated in trance, or samadhi. This yoga practice is more or less based on the principles of the Patanjali system. After hearing this yoga system described by Lord Krishna, Arjuna said,
Oh Madhusudhana, the system of yoga which you have summarized appears impractical and unendurable to me, for the mind is restless and unsteady. The mind is turbulent, obstinate, and very strong, O Krishna, and to subdue it is, it seems to me, more difficult than controlling the wind." [Bhagavad-gita, 6:33-34]
Arjuna was a powerful prince, endowed with great bodily strength, endurance, and fortitude, yet he thought the astanga system impractical and unendurable. So what to speak of the common man of the present age, where strength, vitality, and determination are greatly diminished, and sensual control is almost non-existent. Traditionally in India, the transcendentalists all leave home and reside in sacred places such as Prayag, Mathura, Vrindavana, Hrisikesa, and Hardwar, and in solitude practice yoga where the sacred rivers like the Yamuna and Ganges flow. But it is not easily possible to retire to a secluded place in the mountains or jungles in order to practice yoga in this age of Kali. The present age is characterized by a bitter struggle for a life of short duration. People are not serious about self realization even by simple, practical means, what to speak of the difficult yoga system. The so-called yoga societies in big cities are not at all suitable for the practice of yoga. Those who are imitating this yoga system are certainly wasting their time, and are completely ignorant of the desired goal. Trying to practice yoga while engaging the mind in material enjoyment is like trying to ignite a fire while pouring water on it.
The localized Vishnu-murti is the plenary representation of Krishna dwelling within ones heart. One who has no program to realize this Vishnu-murti is uselessly engaged in mock-yoga practice. One who practices yoga only for improvement in health or aspiring for material perfections is no yogi according to Bhagavad-gita. When we speak of yoga, we refer to linking up our consciousness with the Supreme Absolute Truth. Such a process is named differently by various practitioners in terms of the particular method adopted. When the linking up process is predominantly in fruitive activities, it is called karma-yoga, when it is predominantly empirical, it is called jnana-yoga, and when it is predominantly in a devotional relationship with the Supreme Lord, it is called bhakti-yoga. Bhakti-yoga, or Krishna consciousness, is the ultimate perfection of yoga. Lord Krishna states in Bhagavad-gita,
"And of all yogis, he who always abides in Me with great faith, worshiping Me in transcendental loving service, is most intimately united with Me in yoga, and is the highest of all." [Bhagavad-gita, 6:47]
When jnana-yoga and karma-yoga are dovetailed by enquiry and service to the absolute truth, they also become spiritualized, and are a part of bhakti-yoga. The ultimate goal in this case is Krishna consciousness, and therefore, for a genuine practitioner, there is no distinction between the various methods, as they are rightly situated as different rungs on the yoga ladder. Bhakti-yoga is full spiritual knowledge, and as such, nothing can excel it. Asceticism without self-knowledge is imperfect. Empiric knowledge without surrender to the Supreme Lord is also imperfect. And fruitive work without Krishna consciousness is a waste of time. Therefore, the most highly praised form of yoga practice is bhakti-yoga, or devotional service to the Supreme Lord.
The culmination of all kinds of yoga practice lies in bhakti-yoga. All other yoga's are but means to come to the point of bhakti in bhakti-yoga. Karma-yoga, without fruitive results, is the beginning of the path. When karma-yoga increases in knowledge and renunciation, the stage is called jnana-yoga. When jnana-yoga increases in meditation by different physical processes, it is called astanga-yoga. And when one comes to the point of the Supreme Personality of Godhead, the culmination, it is called bhakti-yoga. The yogi who is progressive is on the true path of eternal good fortune. One who sticks to a particular point and does not make further progress is called by a particular name: karma-yogi, jnana-yogi, dhyana-yogi, raja-yogi, hatha-yogi, etc.
The ideal yogi concentrates his attention on Krishna, Who is called Syamasundara, Who is as beautifully colored as a cloud, Whose lotus face is as effulgent as the sun, Whose dress is brilliant with jewels, and Whose body is flower garlanded. He descends like a human being, as the son of Mother Yashoda, and He is known as Krishna, Govinda, and Vasudeva. He is the perfect child, husband, friend, and master, and He is full with all opulences and transcendental qualities. If one remains fully conscious of these features of the Lord, he is called the highest yogi.
A pure devotee is constantly engaged in bhakti-yoga (devotional service). Sometimes he chants, sometimes he hears or reads books about Krishna, or sometimes he cooks prasadam or goes to the marketplace to purchase something for Krishna, or sometimes he washes the temple or the dishes - whatever he does, he does not let a single moment pass without devoting his activities to Krishna. Such action is full samadhi and the topmost yoga.
There are many mystics and yogis all over the world, but Krishna is the master of all yoga systems. Krishna's instruction is explicitly stated in Bhagavad-gita. "Surrender unto Krishna." One who does so is the topmost yogi. By engaging in bhakti-yoga, devotional service to Lord Krishna, the practitioner automatically surpasses all preliminary yoga practices without separate endeavor. The bhakti-yoga system is applicable for everyone; man, woman, or child, wherein the re-awakening of our constitutional spiritual nature, in loving reciprocation with Krishna, is fully and joyfully manifest.